Apparatus for the control of internal-combustion engines



Aug. 28, 1945; F. B. HALFORD ETAL 2,383,719

APPARATUS FOR THE CONTROL OF INTERNAL-COMBUSTION ENGINES Filed Dec. 5, 1942 10 Sheets-Sheet 1 A CCEL ERA TING PUMP CONTROL I nuenlors all/wrap Aug. 28, 1945. F. B.- HALFORD ETAL APPARATUS FOR THE CONTROL OF INTERNAL-COMBUSTION ENGINES l0 Sheets-Sheet 2 Filed Dec. 5', 1942 Inentor-S 4 9741;? PJWMW;

Attorneys l Au'g. 28, 1945. F. B. HALFORD ElAL 2,333,719

APPARATUS FOR THE CONTROL OF INTERNAL-COMBUSTION ENGINES 1O Sheets-Sheet 3 Filed Dec. 5 1942 Aiiorney:

10 Sheets-Shet 4 Filed Dec. 5, 1942 F. B. HALFO'RD El'AL Aug. 28, 1945.

' APPARATUSFOR THE CONTROL OF INTERNAL-COMBUSTION mamas v Inventors @I/awna- By 737,

Attorney;

Aug, 28, 145; F. B.IHA LF ORD EI'AL 2,383,719

APPARATUS FOR THE CONTROLCF INTERNAL-COMBUSTION ENGINES Filed Dec. 5, 1942 v 10 Sheets-Sheet 6 FIGS.

, A ttorneyq g- 2 1945- F. B. HALFORD ETAL ,7

APPARATUS FOR THE CONTRQL 0F INTERNAL-COMBUSTION ENGINES Filed Dec. 5, 1942 10 Sheets-Sheet 7 E Mw V A Home Afi g. 28, 1945. B BALI-0RD ETAL APPARATUS FOR THE CONTROL OF INTERNAL -COMBUSTION ENGINES 1o Sheets-Sheet 8 Filed Dec. 5, 1942 Invenio; I'd/1002120,

B 1 an/r45 Atlqrneg Aug. 28, 1945. F. B. HALFORD ErAL APPARATUS FOR THE CONTROL OF INTERNAL-COMBUSTION ENGINES l0 Sheets-Sheet 9 Filed Dec. 5, 1942 ainmmnw IFTTJY;

1 n ventozs L d fflbl b w By PI M41445 Attorney:

Aug. 28,1945. B. HALFORD ETAL APPARATUS FOR THE GONTROLOF INTERNAL-COMBUSTION ENGINES Filed Dec. 5, 1942 10 Sheets-Sheet l0 Patented Aug. 28, 1945 APBABATUSWFOR THE; CONTROL or v INTERNAL-COMBUSTION ENGINES Erank Bernard Halford, Edgware, and Percy John Wallace, Harrow Weald, England, assignors' to D. Napier-8a Son Limited, London, England, a. company of Great Britain Arplinationllec ni er 5, 194.2. r al No- 67. ln Great Britain October 13, 1941 7-Claims. (or. 123-119) This inven ion. relates: to ap a a us o h ontro o nt rnal. combusti n en ines sused r th nr pulsionlo aircrait and. has f r ts. ie'ctrt fect uch nterconne ti n of. the. va o s ng e ontr s. as will. result. certain. definit d n a es- As. for nstanc o, ive. elief. o the pilot or. a r raft y providin n y. a gl l r hich it is neces ar o. mov p a e. of sever 'c ntrol' evers, andto rrelate th va ious ntr l mov ents h. ce tain ngine ha a t r stics h r by e. est nsine p rtorman will tend' to be obtained at all times. The ap,-- paratus should also prevent or'rninimise the risk of mishandling the engine.

The following points call for consideration in the dev s ng apha us c aslthat. omprised in the present invention. Faulty manipulation of the engine will have one or more undesirable effects, as for instance it will result in failure to get-therequired power; or this power will. tend to be obtainedat the cost of increased fue l' con sumption and consequent loss of flying range, it may lead to premature wear or evenserious damageto the engine. almostimpossible for the pilot tomanipulate separatel the various engine controls so as to get from the engine the best performance at all times. Thus correct use of the lever controlling the fuel mixture is needed to obtain extreme flying range. Then-to get themaximum rate of climb necessitates change to high gear in, the supercharger drive within narrow limits of altitude andperformance maybe seriously'impaired by premature ordelayed gear change, Again failure to make the necessary gear changes and at the correct times-,may have important practical'. results in the case of; fighter aircraft.

Accordingto this invention a pressure-sensitive capsule is connected to and moves the valves con-. trolling aboost servo motor with aconstant ac tion which is determined only by variations in the boost pressure in the engine induction manifold to which the capsule is subjected, and with this capsule actuated valve there is combined a member which is movable independently of and e in relation tothat valve this member having in it the ports controlled by that valve, and means are provided for moving this ported member and by thus setting it determining datum boost. The servomotor' whose valve is thus directly actuated by this capsule controls the boost pressure by moving the engine throttle and by also regulating automatically the operation of the supercharger. The controlling action of the valve of the boost servomotor-is determined b the mov- With military aircraft it is in-g inrelation to the valve of the ported member and h set in at s member n be fie ted bothby a manually operated lever and automati-. Ca ly b e oo v r bm q hich an t ke c n ol. of he set i oi t i m mb r wh nh a 0 boost pressure occurs. The operation of the supercharger is regulated by actuation of the change gear through which it is driven this change gear being controlled from the piston of the boost servomotor with a superimposed control by the hand lever. This hand lever is operative to control collectively and in correlation a fuel pump, the engine throttle, the ignition, the ported member which determines the datum of the valve control of the boost, servomoton the setting of the airscrew governor and the setting of the carburetor for weak mixture. It is convenient to employ a; piston valve as that which controls the boost servoinotor and this Valve is acted on by one end oithe capsule whose opposite end is fixed. Thi valve moves withina ported sleeve which as mentioned is primarily moved by the hand lever to determine the datum boost, but onv fall of boost pressure "can be moved by; the boost servomotor.

The apparatus serves tomeasure fall of boost pressure above certain critical altitudes and this measured fall of .boost is used to maintain correct ignition timing and to select the moment for changing gear in the supercharger drive.

In this apparatus the boost control is efiected in a manner which may be said to be the reverse of what is customary. In the normal arrangement movement of the hand or pick-up lever serves to give an opening to the throttle which isin excess of that required to give any particular datum boost at ground level and the automatic control then brings back the throttle to the precise opening at which; datum boost is just maintained. The angle through which the throttle is thus automatically closed necessarily limits andin fact is normall equal to the amount by which the throttle-can subsequently be opened up by the boost control in its efiorts to maintain datum boost as the aircraft climbs towards criti cal altitudes. Qn the other hand with the re versed boost control as here employed practically the whole travel of the piston of the boost servomotor is'left "available with increasing altitude to "open further the throttle beyond, the opening given to it by the hand or pick-pf ever.

As employedin the-present apparatus the boost control is able to give full throttle atall' datum boosts Thisis made possible by the inclusion in the apparatus of an overrun mechanism which allows the boost control servomotor to open the throttle fully irrespective of the manual opening associated with the datum boost. The throttle valve itself does not at any time pass beyond the position :where it is parallel to the axis of the Venturi passage in which. the. throttle is placed. Y

The accompanying drawings illustrate by way of example how the invention may be carried out in practice. The mechanism here described and illustrated may be-assembledl in a manner which will permit of substantially all the interconnections between the several controls being grouped together in a single box or casing. It is thus arranged as shown in these drawings in which- Figure 1 is a diagrammatic view showing the general layout of the whole apparatus.

Figure 2 is a diagrammatic perspective view showing how certain of the parts in the apparatus are interconnected and operated through these I interconnections.

Figures 3 and 3a are together a sectional elevation, the section being taken on the broken line 3-3 in Figure 8 and showing some of the principal parts of the apparatus shown substantially as they are associated in the control box, these parts including the pick-up or main control lever and the members actuated through the shaft of this lever, the boost servo motor with the valve which controls it, and what may be referred to as the second servo motor which operates the change gear of the supercharger drive and the valves which control this servo motor. This Figure 3 has been divided in order that the parts shown may there appear on a rather larger scale, but it has been thought advisable to show also, as is done'in Figure 3b, in a single figure, but on a smaller scale, all that is seen in the two parts of Figure 3. Other figures which represent sections through Figure 3 are on the same scale as Figure 3b wherein the lines on which these sections are taken can be more easily seen.

Figure 4 is a similar view showing other parts of the apparatus which are grouped together including the pressure-sensitive capsule, the section being taken on the line 4-4 in Figure 9.

Figure 5 is again a similar view showing certain valves, the section being taken on the line 5-5 in Figure 7.

Figure 6 is a transverse section on the line 65 in Figure 3 looking in the direction of the arrows.

Figure 7 is a transverse section on the line 1-1 in Figure 3 looking in the direction of the arrows.

Figure 8 is a transverse section on the broken line 88 in Figure 3 looking in the direction of the arrows.

Figure 9 is a view looking on the end of the apparatus from the left-hand side as it is seen in Figure 3 and with a portion of the casing removed and parts shown in transverse section,

'Figure 10 is a part transverse section in the plane of the line H) in Figure 3. I

Figure 11 is an end view, parts being in transverse section, of one of the cam transmission mechanisms as seen in Figure 8, but looked at from the opposite side and shown on an enlarged scale, the view being in effect a section on the line HH in Figure 12, looking in the direction of the arrows and with some parts omitted.

Figure 12 is a section on the broken line i 2I 2 in Figure 11 looking in the direction of the arrows.

Figure 13 is a section on the line l3l3in Figure 11 looking in the direction of the arrows.

Figure 14 is a longitudinal sectional elevation on an enlarged scale of the concentric cooperating sleeve valves associated with the changing of the speed gear in the drive of the supercharger.

Figures 15, l6, l7 and 18 are transverse sections of these valves as shown in Figure 14 these sections-being taken respectively on the lines I 5I 5, l6l6, l'!l1 and 18-48 in Figure 14 in each case looking in the direction of the arrows which are shown only with the section line I 5l 5.

In the apparatus now to be described use is conveniently made in several instances of a transmission mechanism forming the subject of abandoned United States Patent application Serial No. 456,064, standing in the names of the present applicants. That mechanism, which for simplicity will herein be referred to as a cam transmission is devised for transmitting movement from one rotatable member to a second, separat and coaxial rotatable member. The construction comprises broadly a lever pivoted on and at a distance from the axis of what may be called the first rotatable member, a connection between this lever and the second and separate rotatable memher, this connection serving as a means for transmitting movement and imparting rotation to the second member as the first member rotates. As the first member is rotated by suitable means the lever carried by itcan be caused to move or to be prevented from moving relatively to that member while it is carried therewith as that member rotates. Such permitted or prevented relative movement between the lever and the first member determines the nature of the movement imparted through the lever to the second memher. A particular construction of such a mechanism is illustrated in Figures 11, 12 and 13 of the accompanying drawings and is described hereunder.

In certain places use is also made of difierential mechanisms. As employed, each of these mechanisms may conveniently comprise bevelwheels arranged oppositely on the ends of two coaxial and rotatable shafts. Between and in engagement with these bevel wheels are bevel pinions, for example two, arranged oppositely in a cage the rotational position of which can be altered. By thus moving the cage so as to alter the angular position of the pinions the angular relation between the two shafts may be altered, or if one shaft is held against rotation the other shaft will be turned through a determined angle according to the angle, through which is turned the cage carrying the bevel pinions.

Certain parts which are here included in this apparatus and dealt with as a whole in combination in this invention form the subject of a separate and copending application for United States of America Letters Patent Ser. No. 458,276, now Patent Number 2,344,547, wherein these parts by themselves are described and claimed as they may be used for general purposes.

Referring first to the diagrammatic view Figure 1, the principal features in the whole apparatus as there shown comprise the following. The pressure-sensitive capsule A actuates a valve 13 which controls the flow of liquid under pressure to the servo motor C. A pick-up or hand control lever D through the shaft D on which it is mounted can move a lever E which is connected to the accelerator pump of the carburettor. The throttle is controlled from the lever F and the ignition from the lever G. In association with the hand lever D and the throttle and ignition controls there are used several of the camz. transmissions mechanisms; referred to: above. Theseere: represented in; Figure 1 by concentric circles: respectively: designated H 1, H H 3 Will? and: H91. and. the connectionsbetween the; two main partseof; each: of' these mechanisms andthe parts with-which they cooperate; in transmitting movements'are represented-by; lines.- Glanried on the; shaft. D; but not directly: connected to-itg. are two difierential mechanism J and? K through whichzand in;- coniunction with the cam transmissiommechanismsI-I H I-F'and: H movement can be imparted to; the. levers: E and: Gs from. the hand lever D and' also; from other. parts of the apparatus; 'The diirerentialJ is: associated: with the transmission of movementstcr the throttle leverF and! the difierential' K is similarly associvalve: V againsta. spring; This valve is moved either by pressure liquidheing-permitted to: flow asetting: or the valve '11 or-bylrotationx Off the and throughitscasing andxabeing used; according v to= the; position of the: valve: U,. tow operate: the servornotor Q* on; occasion. when a; change 2 to low gear is desiredaih: the. superchargerdriveaw-ithout a; setting of the valves:=1VI andiblz As Cambe seen pressure. liquid reaches the: valve either forming part. of? the mechanism by which that lever: moves-the ported: sleeve L. These valves M and? N control,- the fiow'of' liquid under pressure toxtlzrecy linder-oi aserv-omotor 0v which actuates I Movement or the. hand. lever D operating through: the: cam transmission mechanism- I-I can enact a. setting ofthe airscrew. governor;

Movement: which determines the mixturein the carburettor is=transmitted from a lever" Q and: this. lever is. caused to turn; by: movement of the: piston in: the; cylinder of a, servomotor R. Movement of: this: piston; R will also; have an ofiecti through the cam transmission; mechanism H? on the differential K associatedwith the movement or. the ignition lever: G. The movement the? piston Rt of-theservomotorR-i is of.- fnotedby lioiiid under pressure the; flow of: which to: and: from: the cylinder of that servomotor is controlled by a piston valve Sv itself actuated: by liquid under pressure; theflow off which? is: contnollediom theonehand; by the'valves- M and N andi on: the other hand'hy a valve I which is rotated through the gearing from the lever' D;

ThiS-iVE'IVBiT also controls the, flow of pressure liquid: to; actuate a, valve U and a valve-Wand it also controls shadow of, pressure liquid to 1 avalve rotation of which controls the-actuation-vofl the valve by= this'pressureliquid. The valve U is iir were subsidiary tothevalves M and. N. in their controlof thezflow' of pressure liquid: to operate: theservomotor 0. Asmentioned the latter efiects changes in the speed; gear the drive tenths-supercharger. As can-be seen from thanunof the pipes-0r passages indicated byvthe. lines infill-gum 1, the'pressureliquid: entering the interior of, the: concentric valves-M and N passes thencesaccording to the setting of, these valves,

to the ported casing in which movesthe-va'lve U. As this valve. is moved: it permits pressure liquid to flow or drain from. oneendor the other of the servomotor cylinder 0a The longitudinal movement of the. valve U1 againstv the spring acting; thereon. results first from a setting of the valve T and secondly'after longitudinal movement or, the.

through a .pipe or passage leading: from the. cas ing; of thevalvessM: and N, the flow. being. controlled: theend part of: the innervalva N, or fromithe valve T to the interior offwhichipressure liquid-issuppli'ed:

Liquid under" pressure entersthe system from some suitable'source of'supplyatthe places indicated' at :01; where: it. entersthe' mainpartioff the concentric valvesaM and N; at xhwhereit enters a small chamben'in the en'di part: of the inner valve N; andi'at r vv here' itilcan: enter both the casing of'the valve Sandi' alsothe-interior of'the' valve. T. This li'quid can drainfrom within the valves M1 and N as will bedescribed hereunder and" these: valves controlithe draiir. fromlthe valve U. Drain fromthe v valve S1 canatalce place through a port in itscasing.

Turning now" to the more detailed. construction and arrangement of thepar ts off the apparatus; the pressure-sensitive: capsule A", seen in Figures 4; 6 and 8, isxplac'ed where it willlbe exposed-1 to the-pressure i'n the-induction manifold of the engine'. It is disposed in: a chamber A which is in communication by' passages A with the induction manifold. This capsule will thusbe sen-sl tive to boost pressure which itself is determinedby throttle opening and the operation of" the supercharger thelatterbeing variable by altera tions in the change-speed gear through which the supercharger is driven; At one end this cap sule is fixed in that-a projection A f romthecaprsule lies a socket A? in the end wall ofthe chamberA' At its other end the capsule isconnected. to a memherfi whi'ch can sIid'e in aguide A andteeth A constituting a rack are formed alongjone sijdeof the sliding mehiber fii Az similar rack is formed byteeth-B see Figure- 3, on the end portion of the valve B; and'loetweenthese two racks lies a rocking lever B part of which is seen' in Figure, 4 and its position is indicated in chain lines'in Figure'8; Each'arin ofthis lever carries a toothed quadrant, these quadrants en gaging the racks AT- and B and by thismeansexpansionof the capsuleA will cause movement of the, valve B against the action of'a spring B and in the ported sleeve L which itself can be caused to slide, within the casinglb thus altering the, position of the ports in thel sleevein relation to, the. valve 13' which. controls. these, ports; The expansion,andcontraction of thecapsule A causes; themovement. of the valve B an this action of the capsule vv.willhe. constant and'determinecronly bythe boost pressure. in. the engine induction manifold. The .valveLt may. be reierred to. as the boost. valve in .that as. it. is. moved. by, the. capsule A it controls. the flowtof; pressure. fluid. to the cylinder. Got a servo. motor. which may. be referred to assthe-boostservo. Tlhepistonic yinthis cylinder C as it moves cart-have, an; effect. on-;the;onc.'

hand: on: they throttle opening and also. on. the ignition timing, and on the other hand on the change gearin the supercharger drive.

By moving the ported sleeve L in relation to the boost valve B within it the boost datum will be determined. What maybe called the primary movement imparted to the ported sleeve L is effected by a worm thread L on the exterior of an end portion of the sleeve and this thread is engaged by a nut L which when it is rotated will cause sliding of the sleeve, the latter being restrained against rotation. The arrangement is shown in Figures 1, 2 and 3. Rotation of the nut L is cause by movement of the hand lever D acting through a toothed quadrant D on its shaft D see Figures 1, 2, 3 and 7. This quadrant meshes with a toothed quadrantD on a sleeve D rotatable on a fixed part D and carrying a second toothed quadrant D It may be noted that the sleeve D with the quadrants D and D are omitted for the sake of clearness in the diagrammatic Figure 2. The movement is then transmitted through the cam transmission mechanism H of which the chief features inits construction are to be seen in Figure 2, but the parts are also to be seen in Figure'l. This device comprises a toothed member H on a rotatable part I-I with its teeth meshing with the toothed quadrant D The member H has pivoted thereto at H and lying at one-sideof it what is in effect a two-armed lever of which the one arm carries or is constituted by a toothed sector H, while the other arm carries a pin H which lies in a cam slot I-I in a member H mounted on the part H but held against'rotation. The toothed sector H meshes with teeth L on onepart of the nut L Thus when the hand lever D is moved the movement will be transmitted through the several intermeshing quadrants andthe part I-I will be rotated and will carry with it the nut L The movement actually given to the nut L however, will be determined by the contour of the cam sl-ot H With this contour, as shown in Figure 7; as the member H turns the nut L? will at first be caused to turn faster andthrough a greater angle, but as the pin H passes into a difierent part of the cam slot'H the nut will be turned at a slower rate and through a lesser arc than that through which the member H is turned. Such rotation of the nut L will cause a longitudinal movement of the ported sleeve L and it will be appreciated that owing to the interposition of the cam transmission mechanism this movement of the sleeve will not be a regular one as the hand lever is moved through any given angle. I 7 against movement in the axial direction by a member through which on occasion the nutwithout being rotated can be moved in that direction and when so moved it will carry with it the sleeve L. This member L can ,slideon a fixed bar or guide L (see Figure .3) against the action of a spring U, and towards one end it has a forked or like part L which engages a groove in the nut L while at the other end is a lateral projection L through which is imparted to the member L5, in a manner and by means to be described hereunder, a sliding movement against the spring L" which is transmitted to the nut I}. In this way it is possible to effect an independent or secondary setting of the ported sleeve L. Thus in the first place this sleeve L can be set to a determined datum boost by means of the hand lever D, but when a fall of boost occurs a secondary setting will beefiected automatically. I I Y The piston'C in the cylinder c of'the'boost While the nut L is-rotatable it isv held servomotor is mounted on the'en of a hollow rod 0 within which is a spring C whose outer end abuts against a fixed part C on the exterior of which are splines engaged by splines within the outer part of the rod C which is thus guided by the part C and at the same time prevented from turning about its axis. On the outer part of the piston rod C is a quick-pitch thread C and at the inner end of this threaded part isan annular flange C which constitutes a projection adapted to come into contact with the projection L when the piston C has moved through a certain distance. This will occur on reaching a de-' termined altitude when on any further increase in altitude the resultant movement of the piston C will cause it to carry with it the sliding mem-' ber L and thus transmit movement to'the ported sleeve L. The whole assembly comprising the capsule A, the valve B, the ported sleeve L and the piston C of the boost servomotor will then oper ate as a follow-up servomotor in which-expansion of the capsule A due to any fall of boost will pro duce a proportional movement of the piston 0 On the shaft D of the hand lever D is a lever E which is connected to the accelerator pump of the carburettor so that enrichment of the mixture will synchronise with rapid opening of the throttle by the hand lever, the throttle being controlled as mentioned from the lever F. The member 1-1 see Figures 2, 3 and '7, has been de-? scribed above as forming a part of a cam transmission mechanism through which movement can be'imparted to the ported sleeve L-from the hand lever D. This member H is connected to and rotatable with a member H seen in'Figure 3, which forms a part of a cam transmission mechanism through which movement c'an'be imparted 'to the lever 20 by which adjustment of the airscrew governor can be effected in a known manner. Thi cam transmission mechanism H shown in Figures 3, 3 3b, and 9 comprises parts arranged and operating in a manner similar to that described above and shown in Figure 7 of which the member H forms a part. In this case the member H has pivoted thereon at H a two-armed member of which one arm carries a toothed sector H meshing with a pinion 2| on the shaft 22 of the lever 20 (see Figure 3b) The other arm carries a pin which lies and i movable in the cam slot H.

For a detailed disclosure of the air screw governor and its controls, reference is made to United States Patent No. 2,217,364 issued to Frank Bernard I-Ialford et al., October 8, 1940; In brief, the governor and control mechanism comprises a fluid pressure system for directing oil at high pressure to a pump and through a controlling valve to an expansible fluid pressure chamber located in the shaft of the air screw and organized so that changes in the volume of the chamber under the influence of pressure fluid serves to rotate the blades of the screw and change the pitch. The mechanism described immediately above and designated generally H serves to control the operation of this governor and its related mechanism. By operating the lever 20 this leve 20 constitutes the control by means of which the oil directed to the operating chamber is governed.

The control valve of the air screw governor disclosed by the patent referred to comprises a piston valve that is axially movable by an actuating member, designated B in the patent. This thatare driven by the engine, so fli'at thedegree of opening or closingof the fluid pressure line connected with various engine control operators,

such'as anignition control, a change speed mechanism and a boost-control cam. In thedevice of the patent, this modification of the effector the' flyweigh'ts is efiecte'd by changing the spring load upon the actuating member, by a sleeve that moves in opposite directionsto compress or relieve'the helical loading spring. Movement of the sleeveis in directions extending axially of the piston valve, and is disclosed as bein-gaccomplished by a gearwheel, driven from the linksystom-and driving a pinion that meshes with a'rack carried by the cylinder.

I-he herein .disclosed system may be made ftective to operate the governor of theidentified patent-, by-a'link connection between the sleeve of the \governor control and the lever -20 so "that movement of-the sleeve to alterthe loading effect upon thea ctuating member is initiated by the lever 20 and the mechanism H rather than by the linkand lever system andthe rack and pin- .ion'sl'eeve drive of the said patent. By such connection, movement of the handleD of the instant mechanism inone direction will open the valve supplying fluid pressure tothe governor, and oppos'ite movement of the handle will move the valve-toward closed position;

By means of this mechanism-through which theairscrew governor can-be adjusted-there will bemaintained the correct relation between the position of the hand lever Dand engine speed.

case conveniently isintegral with the part H in which is thecamslot H 'of'the'cam transmission mechanism H The -toothed sector H meshes with a toothed sector J 1 mounted on one end of aisleeve lJ on:the-other end of which "is the'bevelzwh'eel J which formspart oi the differential J see .Figure 3a). The opposite bevel wheel li iis mounted on :one :end of a sleeve on theotherl end of WhiChiiS one'part of a two-part member J Ji which bridges the-differential K and is carried ion .a bearing beyond the bevel WheeliK. .On -;this .partJ of the member J is :carried the .pin 11-1 on which turns .the twoarmed imember awhich carries .the toothed sector Hi of 1the cam transmission mechanism H (See Figure-:8.) Itzmay be noted that in Figure 3 i0lll31'l ecS8ke zoficlearance'the bridge piece J is shownzhroken away with :the one part which carries the fpin 1H d isplacedaangularly about the axis of ethezshaft D Thespinions J of the dif- Ierential J .are carried in :a cage member J" mounted 'on a sleeve which can turn on the sleeve awhichzcarries the bevel wheel J and the partial? :This cagemember also carries'an extension J zformed .as a sector with skew teeth whichare tin zengagement withth'e teeth :0 on the mod :of the pistonC .of the boost servomotor C so that as that piston moves-it will swing the cage member Jlzabout the axis of the shaftD and thus. alter the relationship between the two bevelawheels J -and..Jf Through the cam transmission :mechanism H the cage z-member J can turn-tthezmem'ber-K :whichicarries the planetary .-As already mentioned, movement of the'hand leveraD through its shaft =D wil1 cause movement of "the leverJF which actuate the throttle, and also the lever G which controls the ignition timing. Involved in this transmission are four cam transmission mechanisms H H H and H, and two differentials J and K all as indicated diagrammatically in Figure 1. These cam mechanisms are :shownmore in detail in Figures '7 and 8 and can also-be identified in Figure 3a where are seenthe two differentials.

Taking-first the cam transmission mechanism H ,-the member'D mounted on a sleeve keyed to the hand lever shaft D carries the toothed quadrant'D and also the pivot pin H on which can turn the two-armed member which has one arm constituted bythe toothed sector H wh'ile the other arm carries the pin H which lies in the cam slot H formed in the fixed part -H' ('see Figure '7). The toothed sector H meshes with apinion K -mounted on the oneend of a sleeve'li onthe other end of which is mounted the 'bevel' wheel K "forming a part of the dinerential K (see Figure 3). The opposite bevel wheel 'K is mounted'on the end-of a sleeve G which at its outer-endcarries the lever G through which the ignition timing is controlled. Withregard to the cam transmission mechanism H the-member D carries also the 'pivot pin H (see Figure '7) on whichcan'turn the twoarmed member of which the one arm-is constituted by the toothed sector H and-the othercarries the quin'H awhichirlies in the camislot H 2.111 the :part .H "which .i :fixed and sin this pinions K of .1the.;difierentia1 .K. This member K :-;can turn on apart of the shaft-D which lies between the :bevel aw'heelsdi and K iOn ithe zcage member .J is .carried the pivot pin 11-1 of :the cam transmission mechanism H which together withthe cam'transmission mechanism 'H? :can be .:seen in Figure '8 in end 'view while their relationship in .-the longitudinal direction c0211. be gathered "from :Figure 3."It should-be noted that fortthe::sakeof clearness in Figu-refiipartseofithe diffierential ,K, which should appear have been omitted. xOn the pin H can turnsth'e twoearmedvmembervoi which one arm is constituted by ;the toothed sector H while the other arm '.-.'carries ';the pin 'l-l which lies in the cam s-lot:l-l 11111 :the .member H This cam tramnission mechanism .difiers in some respects from :the' others -=and isgshown more in detail in Figures .11,.1-12: :and 13. In:.this case\instead of thepart'v in'which tisat'he camslot being fixed it is movable the part H zbeing formed-asa slotted link, .as *sefindllsFigllI'B all, which is suspended at one-end'iromvarhollowpin 30 mounted eccentrical ly onqone endportionof the rod R of the piston :of the -;servomotor iR. Helical splines or teeth :R on'.this-.=pistoncrod engage the eccentric pin; or: nut (30 so=thatxit wil1 be turned when the piston -R .-0f.:the5seril0mot0r moves. Towards its otherendzthe linkEI-I I has in it a slot 3-! in which lies a guideipin 32 .on a "bar 533 which can turn OrirDCk in .bearings at its ends. 'With this "construction awhen -2the ,;piston5R; :of the servomotor R..moves',=thexposition of the whole link'H will ber'altened with; respect: to Ithe :axis (if the 'memb.er;-K and "consequently ,rthegrotational efiect in the tnansmissionof movement between 'the cage member;J:7,a-which :carries the pivot H and the memheriKi wiltbe varied.

Throughlithe cam'.transmissiommechanism H movement is itransmitted to i the throttle lever This IGVLQIILiS .mounted on one end of a sleeveF onf'thentherandinner endof Whichis a toothedlever G first through the cam transmission mechanisml-P, and then through the bevel wheels K and K of the difierential K. The throttle lever F canbevmoved by the piston C of the boost servomotor acting through the member J and turning the cage J7 with the pinions J of the differential J whereby since the bevel wheel J is held ,againstrotation the bevel wheel J will be turned with the efiect, mentioned above. The rotation of the cage J acting through the cam transmission mechanism H will swing the bevel pinions K of the differential K and cause the bevel wheel K to turn with efiect on the ignition leve G. As already mentioned some adjustment will be made in the cam transmission mechanism H when the piston H of the servomotor Bis caused to move.

- No matter what may be the datum boost and the associated manual throttle opening, the ported sleeve L is always picked up by the boost piston C through the member L L L at the same point in the stroke of that piston. Thus the attainment of actual full throttle is always identified by a definite and constant angular position of the bevel pinion cage J in the throttle differential J. As mentionedabove th'is cage J" is connected to the bevel pinion carrier K of the difierential K associated with the ignition timing the connection being through the cam tranmission mechanism H The design of this cam transmission mechanism is such that no movement of the pinion carrier K will take place until the pinion cage J has been moved into a position corresponding to pick-up of the ported sleeve Lvby the boost servo piston C From that point the two differentials J and K rotate; in company to advance the ignition an amount proportional to the fall of boost.

To recapitulate, the pick-up or hand lever D is directly connected to the plate D on which is the toothed sector D and this actuates the cam tranmission mechanism H through which movement is imparted to the ported sleeve L. It also actuates the cam transmission mechanism H by which adjustment of the airscrew-governor is effected. The sector plate D valso carries the pivot pin H which actuates the cam transmissiOn mechanism H through which the th'rottle is actuated from the pick-up lever, and also the pivot pin 1-1 of the cam transmission mechanism I-I through which the ignition timing is adjusted. The cam transmission mechanism H provides the means whereby there may be obtained the desired relationship between the hand lever movement and the throttle opening effected by this levertD. In accordance with the above described arrangement for the reversed boost control the full range of throttle opening efiected by movement of the hand lever D is preferably less than the movement requisite to open the throttle valve fully. Consequently there exists a mechanical advantage in the control which is availableto reduce the manual efiort necessary to open the throttle. The cam transmission mechanism H and the differential K through wl'iich, manual adjustment of the ign tion timing can be, effected, enables correct timing to be obtainedfor all engine speeds at corresponding datum- =boosts and under normal rich mixtureconditions.

The controls indicated aregrouped and on; closed in a suitable casing. Within this casing are disposed all the principal part referred to; above and the only connectionsexternal tothis'. casing comprise the links respectively to .the throttle valve from the lever F, to theaccelerator,

pump from the lever E and the weak mixture,

lever on the carburettor from the leverQ, to the, ignition unit servo from the lever G, to the goV-. ernor from the lever 20, and to the change-speed lever of the supercharger gear P Two connecting links pass to the pilot's cockpit for the hand,- lever D and for the optional low gear lever W: In addition there are the usual boost pressure connections and oil pipes both for supplying liq-' uid under pressure and for drainage,

The weak mixture necessary for economical cruising is brought into operationover the appropriate range of engine speed pby means of the separate small servomotor R the movementof the piston R in which is controlled by the rotary valve T actuated by gearing from the shaft D of the hand lever D. The gearing through which this valve T is rotated is arranged as follows, ref-,;

erence being made more particularly to Figures 1, 2, 4 and 7. On the end of the valve T are teeth T and these mesh with the toothedsector H which is the driving member of the camv As has been mentransmission mechanism H tioned above this sector I-I meshes with, the toothed quadrant B, see Figure 7, which is in-... tegral with the toothed quadrant D in mesh with the toothed quadrant D on the shaft of the hand lever D. Thus according to the position, of the lever D liquid under pressure will be ad-' mitted to one side or the other of the pist0n:R

of the weak mixture control servomotor R. In this way the employment of a Weak mixture becomes compulsory over a certain range of engine speed and in relation'to the determined datum:

boost.

As has been stated in the previous general deg,

scription of Figure l the actual control of thev admission to and outflow from the cylindenoi. the servomotor R is effected by movement of the,

valve S, but this valve is moved by pressure liquid the flow of which to the valve S is controlled by the valve T and also by the concentric and cooperating valves M and N which will be more fully described hereunder. Liquid under pressure enters at :0 and passes to ports in the casing S of the valve S and separately also to a port in.

the casing T of the valve T. Thus when rotation of the valve T, due to a movement of the hand lever D, permits pressure liquid to flow into the valve casing S and move the valve S against the spring S which acts thereon, pressure liquid will be admitted to one end of the servomotor cyle inder R and the other end of this cylinder will be open to drain. The nature of this control of the weak mixture is such that while a slow movement of the hand lever D will cause weak mix-.

ture to operate over the determined speed range,

on the other hand a rapid movement of the hand lever, as may occur when accelerating forthe take-oil of the aircraft, will not cause weak mixture to be introduced but normal rich mixture will be maintained.

valve N which controls the flow of pressure liquid through a circuit which will cause this pressure to act on and move the valve 5. This rotational setting of the valve N will be caused when a predetermined fall of boost from the datum boost has occurred at high-altitude as described hereunder. i i

There will now be described the detail construction of the concentric valves M, and N and also the arrangement and operationof the valves U, V and W and their association with the valves M and N in the control of the servomotor O which effects the gear changes Reference should be made to the detail views of the valves M and N in Figures 14 to 18, also to Figuresfi, 7 and 9, and to Figure 1 for the general interrelationbetween these valves. I a

With respect to the valves M and N it should be noted that such valves together with other parts of the present apparatus, namely the capsule A, the servomotor C with its valve B actuated by the capsule, the ported sleeve adapted to be set by means of a hand lever, and means for rotating the valve M by-movement of the piston of the servomotor C, and means for rotating the valve N when the hand lever is moved, all in combination for the purpose of controlling mechanism, form the subject of a copending application for United States of America Letters Patent Serial No. 458,276 by the present applicants. In that case these parts are described as intended for useby themselves or otherwise and for such purpose as may be desired. In the present application however, these parts are employed not by themselves, but as forming part of a general combination and as cooperating with other apparatus, as herein described, in the control of'an internal combustion engine as used for the pro pulsion of an aircraft.

It will be seen from Figure 14 that within the inner sleeve valve N is a transverse partition N which separates off a chamber N opento the interior of the hollow shaft N above pressure liquid can drain through a this shaft and from the chamber N as a result of the appropriate setting of the valves;M and N this liquid having come from the cylinder of the servomotor O. In the part of the sleeve valve Nwhich surroundssthis chamber N there are ports N and N which can be brought alternatively into register, by relative rotation of the valves M and N, with a port M in the part of the sleeve valve M which 'sur'roundsthis part of the valve N.. These ports can cooperate with either the port 4! or the port 42 in the casing 40 (see Figure these ports being in communication by pipes or passages indicated in Figure l which run to the .casing of the valve U. Through these ports 'in the casing pressure liquid can flow away from either end of the cylinder O by way of the casing of the'valve U as determined by the position of that valve. The valves M and N can thus control the movement of the valve U by pressure liquid entering at the end of its casing, as shown in Figure 1, and also the how of pressure liquid into the main part of the casing of the valve U which in turn controls the flow of this liquid to the servomotor O. The valves M and N also control the drain of liquid from the end and main part of the casing of the valve U. a

. Referring now to the transverse section shown in Figure 16 it will be seen that in this part of the sleeve valve N there are two ports N and N and either of these by rotation of the valve As mentioned thence into the right hand end of the cylinder' Got the servomotor. At this time the relative positions of the valves M and N will be such that the drain ports N M and 42 will all be in register (see Figure 15) so that pressure liquid can flow away from the casing of the valve U and thus from the left-hand end of the servomotor cylinder 0, the liquid passing into the chamber N and then away to drain through the shaft N The port 44 (see Figure 16) in the casing 40 communicates with a port in the casing of the valve U and therefore when the ports N and M are in register and also with this port 44 pressure liquid can flow into the casing of the valve U and thence to the left-hand end of the cylinder 0 as seen in Figure l, causing the piston O to move to the right. This is possible since at this time the ports N and M will be in register and also with the port 4! (see Figure 15) thus permitting pressure liquid to flow from the righthand end of the cylinder 0 into the casing of the valve U and .from that casing into the chamber N and thence away through the hollow shaft N The chamber N formed within the main part of the sleeve N is closed by a plug 50 in which is a partition 5| separating ofi a chamber 52. Into the chamber N liquid under pressure can enter through .a port 45 in the casing and a port N in the valve N when these ports are in register (see Figure 18). The port N leads from the corresponding opening in the wall of the plug 50. The supply of this pressure liquid comes from a suitable source by way of the point Pressure liquid coming from the source as can enter the chamber 52 through a port 46 in the casing, a port M in the sleeve valve M and a port N in the valve N (see Figure 17). This liquidcan flow; through a port N and a port 41 in the casing (see Figure 18). As indicated in Figure 1 pressure liquid admitted to the chamber 52 passes from this chamber through these ports either to the valve W or to act on the end of the valve S and move this'valve against the spring S It will be seen that at this end the wall ofthe sleeve valve N is thickened to lie against the interior of the casing 40 since the sleeve valve M is'of less length than the valve N. By suitably designing the gearing through which is moved the ported sleeve L within which lies the boost valve-B, and in conjunction with this the gearing L L L and N it is possible to rotate the sleeve valve N :with a fall of boost at the same rate at which it was rotated in the opposite direction when being set by the hand lever D when this was moved to select the datum ilooost by moving the sleeve L. Consequently the position of the port N in the enlarged end part of the valve N in relation to the port 41 will be in accordance with the actual boost pressure obtaining at any momentin the engine induction manifold. By this means there is provided weak mixture automatically when the boost pressure has fallen to a predetermined figure at a high altitude and irrespective of the engine speed since, as described albove, the ports leading into and from thecham'ber 52 determine the flow of pressure-liquid whichca'n act on the valve S and "thuscause movement 'of'jthe piston in the servo motor R and resultant movement of the lever Q i open position.

Itjis desirable that the pilot shall be able to override' the automatic gear change in order to e'fiect economical cruising at'high altitudes. At the same time it must be possible for him to exer- "cise'this option only whena weak'fuel mixture is being used. This condition is met iby providing the override control valve W, already referred to,

-whi-ch,'as is to be seen from Figure 1, is depend-' font for the flow of pressure liquid thereto upon the pressure liquid circuit which is operative to move the valve S and bring about-a weak mixture through the servomotor R and the lever Q. Presjsure liquid can also flow to the valveW from the valve T to which this liquid comes at m (Figure 1); Thus this over-ride valve Wis only efiective -w-hen pressure liquid has been allowed to flow into the circuit controlling the weak mixture. As can be seen from Figure 1 one supply of pressure liquidcomes from the chamber 52 in the rotatable sleeve valve N and when this valve is set so as to permit this now, the pressure liquid 'can' act'on-and move the valve S which controls the movementof the piston R in the servomotor-R.

Above'the altitude at which this override becomes operative thepil'ot cannot pass from high gear in the supercharger drive at the higher boost pressures to economicalcruisin-g in low gear withoutfirstpassing through the'conditions of economical "cruising in high gear. In this way the "possibility of there-being adisco-ncerting fall of engine power is avoided." v I It ma not always desirable to' change up =to'-"a'high"-gear in the supercharger drive at ongine 'speedsin excess of a" determinedmairimum. This requirement is provided for by adding'a port to" the valve T which'is actuated bythe hand ilever. By means 'ofthisportT' the valve T can control the flow of pressure fluid which actuates the'valve U in such a way as to open the pressure liquid circuit of the servomotor O todrainq This tprev'ents the change'into high gear when any engine speed above the determined maximum is selected* by the hand lever. The automatic change' down to low gear remains unaffected and operates at allenginespeeds.

* It wouldbe possible to arrange the convention'al type of boost control-with a reversed action 'so that in the event of puncture of the capsule there would result one or other of the following effects." First th iston of the boost servomotor would becaused to go permanently to the altiti'rde position and this would leave the pilot with-"little choice of being albletQ use anything much less than maximum engine power and in consequence landing of the aircraft would be dangerous. Alternatively the effect would be to cause the piston'of the boost servo motor to go "permanently to the groundTposition, when the pilot woul;d'be free to land safely, {but would have onlylow engine powerjavailalble at an material altitude." In contrast to this in the present invention the use of reversed action boost control does not suffer from either of these objec- 'wlii"ch connected to the carburettor. In order tions. Owing to the method adopted'in this invention of selecting datum boost by setting of the sleeve L the ports in which are controlled by the valve B of the boost servomotor C, this valve being moved directly by the capsule A insteadof by a, compression adjustment of the capsule itself, then if; this capsule is punctured the pilot is leftwith control of-the engine power from'rnaximum downto fully closed throttle.

In anyengine it isfnecessary to'cut out the action of the boost control over the lower range of pick-up movementso that adequate control may be maintained for ftaxying'on the ground. When reversedaction boost control is used as in the present case this necessitates keeping the histon of jtheboost servomotor C in the ground position. In'the'present arrangement this is effected by setting of the "ported sleeve Land selection' of a datum'boost "which is lower than can easily be maintained with a degree of manual adjustment of the throttle opening for which provision has been made. For example normally this selected datum boost might be about minus u ds. 1 I,

In the present apparatus in the eventof the capsule A being punctured its expansion is limited by cominginto contact with some part of thejcasing, Then the, condition necessary for maintaining full engine throttle with a punctured capsule is that theselected datum boost at zero position of the hand lever D shall be less than that corresponding to the maximum expansion permitted to a punctured capsule.

Itis proposed to use a capsule of normal olesign the one end of thefca'psule being fixed in a sense permanently by, apart A carried by the capsule engaging the fixe i member A the ar ran'gement beingjsuch as only to give provision for such primary adjustment as may be neces- 40 sary without any "means of alteration during oporation so that'the capsule is constant in its action in moving the valve B of the boost servomotor. o

' What weclaim. as our invention and desire to secure by Letters Patent is:

1. In apparatus for the control of internal combustion engines vas used'for the propulsion of aircraft said engines including the usual manifold, supercharger, timer, throttle, supercharger drive, airscrew and governor of usual construction, the combination of a hand lever operative to control the fuel supply, a differential gear and means bywhich this hand lever is operative through this gear to actuate the throttle, a second differential gear with means Whereby the said hand lever is operative through this diiierential gear tovary the ignition timing. a ported sleeve with gearing through which this sleeve can be movedby the said hand lever, a pressure sensitive capsule disposed where it will be subject to the boost pressure in the engine induction manifold the capsule having a constant action determined only by this boost pressure, a valve disposed and movabe within the said ported sleeve. and controlling the ports in that sleevev which can be moved by the said hand' lever in relation to the valve, means by which this valve ismoved by the said capsule, a boost servomotor controlledby the said capsule-actuatedvalv'e, a second servomotor operative to bring-about ajgear changein the'drive to a su- .percharger, means by which the said second servomotor is controlled by the said boost servomotor,

actuate the throttle, and means whereby the said hand levercan control the said second servomotor: and is also, operative on the airscrew govercernor 2. Apparatus for the control of internal combus'tion engines as used ion the propulsion of aircraft comprising injcombination the features .set out in claim 1 in which there is combined with the said controls at least two mechanism for imparting movement from one'rotating membernto a second separatebut coaxial rotatable member, eachsuch mechanism comprising in combination a lever. pivoted on and at a distance ffr'om the ax'isnof the said first member, aconne'ctio'n between this lever, and the said, second "member, and means wherebytas the f rst member. is rotated the lever will-be .causedtomove or will be restrained from moving relatively to thefirst member, the action of .such constraining means on the lever determining the movement if any imparted to the second member as the, first member rotates.

3. In apparatus for the control of internal combustion engines as used for the propulsion of aircraft said engines including the'usual manifold, supercharger, timer, throttlesupercharger drive, air screw. and governor of usual construction, thecombin'ation. of a hand lever, means -whereby movement of this lever .is operative to is actuated by the said capsule, a servomotor ac-,

tuated by liquid under pressurethe flow of pressure liquid to the. servomotor being controlled by the said capsule-actuated valve, and 'means whereby this servomotor controls automatically the gear change in a supercharger drive with means for associating low gear with weak fuel mixture, and means whereby at ultra highaltitudes this servomotor controls the carburettor setting for weak mixture.

4. Apparatus for the control of internal combustion engines as used for the propulsion of aircraft comprising in combination the features set out in claim 1 in which means are provided whereby the .hand lever remains efiective to control engine power in the event of failure of the capsule asfrom puncture. I V

5. In. apparatus forthe control of internal combustion engines asused for the propulsion of aircraft said, engines including the usual manifold, supercharger, timer, throttle, supercharger drive, airscrew and governor of usual construction, the combination of a pressure sensitive capsule disposed where it will be subject to the boost pressure in the engine induction-manifold this capsule having a constant action determined only by this boost pressure, a servomotor actuated by liquid under pressure, a piston valve controlling the flow of pressure liquid to this servomotor, means by which this valve is actuateclby the said capsule, a ported sleeve within which the said capsule-actuated valve lies and can be reciprocated, this sleeve being movable in the direction of its axis to alter the position of the spqllls thereinin relation tmthe said; piston valve within it, a secondservomotor actuated byliqllld underpressureand operativ to vary a speed gear in the-drive-for a-supercharger, two concen- .tric valves which co operateand controlthe flow of pressure liquid to and thus the action; of the said secondservomotor, a hand lever, meansby which this hand lever is operative to actuate ,the throttle, controlthejgnition timing and the, fuel supply, ;move the said ported sleeve and setthe airscrew governor, means by which the said first servomotor can actuateone of the said concentric valves and thereby control the. operationof the said second servomotonwmeans whereby the said first servomotor can control :the,-,-throttle opening, means by which the second of the said concentric valves canbe actuated byrthe said hand lever andalso; by the saidfirst servomotor after its piston has moved a determined distance, a third servomotor actuated by liquid under pressure and'operative tovary the fuel is provided with a valve 'moved-thereby which controls the flow of pressure liquid which is operative to cause the: said second servomotor to effect a change into low gear in the gear drive for the supercharger. v 1 Y '7. In apparatus for the, control of internal combustion engines as used for the propulsion of aircraft said engines including the usual mani- -fold,;supercharger, timer, throttle, supercharger drive, airscrew and governor: of usual construction, the combination of a pressure sensitive capsule, a casing, enclosing this-capsule, an abutment anchorage for the .one end of this capsule in the said casing this abutment except for-primary settin being fixed, a pipe connection'between .thiscasing and the engine induction manifold such that the capsule will be subjected to changes in the boostpressure in that manifold, a servomotor actuated by liquid under pressure, a slid- .ing valve controlling the flow, ofpressure. liquid to this servomotor, a connection between-the said capsule and. this valve such that when the capsuleis caused'to expand or contract, it will actuate the valve, a movable member in contact with which the said valveslides, ports in this movable member whichware controlled by-- the valve as it slides, connections for the pressure liquid between the ports in this movable member .and the said servomotor, means for moving this ported member. and thereby altering the position of the ports therein in relation to the said capsule actuatedcvalve, a supercharging blower delivering, into the. engine induction manifold and determining the boost pressure in :that manifold, means forv varying the effective operation of this superchargenand means whereby the said servomotor controls the operation of the supercharger and thus controls the boost pressure. FRANK BERNARD PERCY JOHN ,WALLACE. 

